A strain gauge can measure the strain or deformation of an object. Typical strain gauges are based on the change in resistance of a metal undergoing strain. For example, one type of strain gauge includes a metallic foil pattern that may be attached to an object, so that deformation of the object deforms and changes the electrical resistance of the foil. A measurement of the change in the electrical resistance can thus provide a measure of the strain or deformation of the object. Strain gauges can measure other physical quantities such as force, acceleration, pressure, torque, or even temperature by placing the strain gauge on an object that has known deformations in response to the physical quantity being measured. In particular, a measurement of the strain may indicate an ambient or applied physical quantity.
The drawings illustrate examples for the purpose of explanation and are not of the invention itself. Use of the same reference symbols in different figures indicates similar or identical items.